With the quick development of science and technology, the electronic device can be given more functionality to enhance the cost-performance ratio of the electronic device. The electronic device having multi-function usually need to be configured more electronic components inside thereof. These electronic components increase not only the circuit density of the electronic device, but also the operating temperature of the electronic device. In order to avoid that the electronic device is overheating during the operation, the electronic device will be usually provided with a fan inside thereof. The electronic device in operating can be dissipated heat by the rotation of the fan. The operation of the fan is controlled by a fan chip so that the fan in operation is able to reach the required rotational speed.
The Fan chip usually controls the operation of fan by two pins, for example, input pin and output pin. In the past, by the use of the two pins, the fan chip is only used to implement the controlling of the rotation speed for the fan according to the use of the two pins. If the fan chip needs to be configured more pins in order to achieve other controlling, further. However, the fan chip increases the number of pins thereon, which is not necessarily compatible with communication interfaces (such as I2C, SPI, UART) in current electronic device. Furthermore, the electronic device may not have sufficient space to accommodate more pins in the trend of miniaturization.